This invention relates to a lubricating system for a combustion engine and more particularly to an improved system for insuring that the engine receives adequate lubricant under all running conditions.
Obviously, it is essential that an engine be provided with adequate amounts of lubricant under all running conditions. Although this ideally is desirable, there are certain types of engines and certain running characteristics wherein this may not be always possible. For example, one form of engine, the two cycle type, normally employs an arrangement for supplying metered quantities of lubricant to the engine for its lubrication during its running since the engine is not provided with a closed lubricant recirculating system. With two cycle engines, the lubricant may be delivered to the engine for its lubrication by mixing it with the fuel. Alternatively, separate lubrication systems have been proposed wherein the lubricant is delivered to the engine independently of the fuel. In either type of system, it is normally the practice to control the amount of lubricant that is delivered to the engine in response to a running characteristic such as engine speed. For instance, a conventional charge forming system employing either a carburetor or a fuel injection nozzle and in which the lubricant is delivered to the engine with the fuel will vary the amount of lubricant supplied as the throttle opening changes. Of course, when the lubricant is mixed with the fuel the amount of fuel supplied will be so varied. In many conditions, however, the actual position of the throttle valve is not fully indicative of the engine lubricant requirements.
In marine vehicles, when the engine throttle is rapidly closed, the vehicle may not readily slow since it does not have a separate braking system as a land vehicle has. Therefore, even though the throttle is closed rapidly, the engine speed will still be high. However, when the throttle position is utilized to control the amount of lubricant supplied, then the lubricant may be inadequate for lubricating the engine.
It is, therefore, a principal object of this invention to provide an improved lubricating system for an engine that will provide adequate supplies of lubricant under all running conditions.
It is a further object of this invention to provide a lubricant supply system for an engine of the type wherein the quantity of lubricant is controlled by throttle position but where additional lubricant will be supplied when the throttle position is not accurately indicative of the lubricant requirements.
It is a further object of this invention to provide an improved lubricating system for a marine propulsion device, particularly one of the two cycle type.